Versatile RNA Interference Nanoplatform for Systemic Delivery of RNAs

Development of nontoxic, tumor-targetable, and potent in vivo RNA delivery systems remains an arduous challenge for clinical application of RNAi therapeutics. Herein, we report a versatile RNAi nanoplatform based on tumor-targeted and pH-responsive nanoformulas (NFs). The NF was engineered by combination of an artificial RNA receptor, Zn(II)-DPA, with a tumor-targetable and drug-loadable hyaluronic acid nanoparticle, which was further modified with a calcium phosphate (CaP) coating by in situ mineralization. The NF can encapsulate small-molecule drugs within its hydrophobic inner core and strongly secure various RNA molecules (siRNAs, miRNAs, and oligonucleotides) by utilizing Zn(II)-DPA and a robust CaP coating. We substantiated the versatility of the RNAi nanoplatform by demonstrating effective delivery of siRNA and miRNA for gene silencing or miRNA replacement into different human types of cancer cells in vitro and into tumor-bearing mice in vivo by intravenous administration. The therapeutic potential of NFs coloaded with an anticancer drug doxorubicin (Dox) and multidrug resistance 1 gene target siRNA (siMDR) was also demonstrated in this study. NFs loaded with Dox and siMDR could successfully sensitize drug-resistant OVCAR8/ADR cells to Dox and suppress OVCAR8/ADR tumor cell proliferation in vitro and tumor growth in vivo. This gene/drug delivery system appears to be a highly effective nonviral method to deliver chemo- and RNAi therapeutics into host cells.National Institute for Biomedical Imaging and Bioengineering (U.S.)National Institutes of Health (U.S.)AXA Research Fund (Postdoctoral Fellowship)National Research Foundation of Korea (Postdoctoral Fellowship 2013R1A6A3A03)National Research Foundation of Korea (Grant 2009-0080734

Capillary Assembly of Anisotropic Particles at Cylindrical Fluid-Fluid Interfaces

The unique behavior of colloids at liquid interfaces provides exciting opportunities for engineering the assembly of colloidal particles into functional materials. The deformable nature of fluid-fluid interfaces means that we can use the interfacial curvature, in addition to particle properties, to direct self-assembly. To this end, we use a finite element method (Surface Evolver) to study the self-assembly of rod-shaped particles adsorbed at a simple curved fluid-fluid interface formed by a sessile liquid drop with cylindrical geometry. Specifically, we study the self-assembly of single and multiple rods as a function of drop curvature and particle properties such as shape (ellipsoid, cylinder, and spherocylinder), contact angle, aspect ratio, and chemical heterogeneity (homogeneous and triblock patchy). We find that the curved interface allows us to effectively control the orientation of the rods, allowing us to achieve parallel, perpendicular, or novel obliquely orientations with respect to the cylindrical drop. In addition, by tuning particle properties to achieve parallel alignment of the rods, we show that the cylindrical drop geometry favors tip-to-tip assembly of the rods, not just for cylinders, but also for ellipsoids and triblock patchy rods. Finally, for triblock patchy rods with larger contact line undulations, we can achieve strong spatial confinement of the rods transverse to the cylindrical drop due to the capillary repulsion between the contact line undulations of the particle and the pinned contact lines of the sessile drop. Our capillary assembly method allows us to manipulate the configuration of single and multiple rod-like particles and therefore offers a facile strategy for organizing such particles into useful functional materials

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

3D Polymer Architectures for the Identification of Optimal Dimensions for Cellular Growth of 3D Cellular Models

Organ-on-chips and scaffolds for tissue engineering are vital assay tools for pre-clinical testing and prediction of human response to drugs and toxins, while providing an ethical sound replacement for animal testing. A success criterion for these models is the ability to have structural parameters for optimized performance. Here we show that two-photon polymerization fabrication can create 3D test platforms, where scaffold parameters can be directly analyzed by their effects on cell growth and movement. We design and fabricate a 3D grid structure, consisting of wall structures with niches of various dimensions for probing cell attachment and movement, while providing easy access for fluorescence imaging. The 3D structures are fabricated from bio-compatible polymer SZ2080 and subsequently seeded with A549 lung epithelia cells. The seeded structures are imaged with confocal microscopy, where spectral imaging with linear unmixing is used to separate auto-fluorescence scaffold contribution from the cell fluorescence. The volume of cellular material present in different sections of the structures is analyzed, to study the influence of structural parameters on cell distribution. Furthermore, time-lapse studies are performed to map the relation between scaffold parameters and cell movement. In the future, this kind of differentiated 3D growth platform, could be applied for optimized culture growth, cell differentiation, and advanced cell therapies

Fabrication and characterization of luminescent Pr3+ doped fluorapatite nanocrystals as bioimaging contrast agents

Fluorapatite doped with rare-earth elements has a wide-range of biomedical applications. Here, a new type of fluorapatite nanocrystals doped with praseodymium (FAP-Pr) with excitation-emission profiles in visible part of the spectrum is fabricated. Energy levels of Pr3+ activator ion contain metastable multiplet states that offer the possibility of efficient multicolor emission lines in FAP nanocrystals. Three types of FAP-Pr nanocrystals with 0.1%, 0.5% and 1% atomic percent of Pr3+ (along with the undoped FAP control sample) are studied. Their novel chemical production method is described, the FAP-Pr nanocrystals structure, biocompatibility and the suitability for cell imaging are analyzed. Physicochemical characterization confirms crystals down to nanometer size. In addition, quantum-chemical calculation predicts that Pr3+ ions are incorporated into the FAP crystal lattice at Ca2 (6 h) sites. In vitro viability results shows that FAP-Pr nanocrystals are nontoxic to live cells. Additionally, the cell uptake of the FAP-Pr nanocrystals is studied using fluorescence-based widefield and confocal microscopy. The nanocrystals show characteristic green emission at 545 nm (3P0→3H5 transition of Pr3+ ion) and orange emission at 600 nm (1D2→3H4), which we use to discriminate from cell autofluorescence background. Orthogonal projections across 3D confocal stacks show that the nanocrystals are able to enter the cells positioning themselves within the cytoplasm. Overall, the new FAP-Pr nanocrystals are biocompatible and of the tested types, the 0.5% Pr3+ doped nanocrystals show the highest promise as a tracking nanoparticle probe for bioimaging applications.The peer-reviewed version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3276

pH-Controlled Gas-Generating Mineralized Nanoparticles: A Theranostic Agent for Ultrasound Imaging and Therapy of Cancers

We report a theranostic nanoparticle that can express ultrasound (US) imaging and simultaneous therapeutic functions for cancer treatment. We developed doxorubicin-loaded calcium carbonate (CaCO₃) hybrid nanoparticles (DOX-CaCO₃-MNPs) through a block copolymer templated <i>in situ</i> mineralization approach. The nanoparticles exhibited strong echogenic signals at tumoral acid pH by producing carbon dioxide (CO₂) bubbles and showed excellent echo persistence. <i>In vivo</i> results demonstrated that the DOX-CaCO₃-MNPs generated CO₂ bubbles at tumor tissues sufficient for echogenic reflectivity under a US field. In contrast, the DOX-CaCO₃-MNPs located in the liver or tumor-free subcutaneous area did not generate the CO₂ bubbles necessary for US contrast. The DOX-CaCO₃-MNPs could also trigger the DOX release simultaneously with CO₂ bubble generation at the acidic tumoral environment. The DOX-CaCO₃-MNPs displayed effective antitumor therapeutic activity in tumor-bearing mice. The concept described in this work may serve as a useful guide for development of various theranostic nanoparticles for US imaging and therapy of various cancers